Originally Posted by
woodfinx
Yeah the problem with that is (at least of what I could find) is that all the minimum IFR altitudes in that part of the country are in class E airspace. I imagine that over all of the continential U.S. it is only an academic theory and not actually able to be performed.
Take a look at this piece of airspace:
SkyVector.com - Aeronautical Charts - Flight Planning
Class G goes to 14,500. At 12,500 you are 2000' above the nearest obstruction for much more than 4 NM and still 2000' below Class E.